Sfi radiator fan?

[71DodgeDemon340]

Hey guys i been thinking, are the old fans ok to run higher rpm say 5-6k ? I have a original one on my 340 and just curious, been up to 4k plenty of times and no issues. Think i need to change? If so any recommendations? Im running a fan spacer as well

 

[TrailBeast]

I don't know the SFI rules but I know they can make a giant hole in a hood when they let go. LOL
Had one let go at 6,000 once on a 440 magnum and the damage was considerable and I was surprised it didn't just rip the water pump off when it went off balance.

 

[71DodgeDemon340]

Any recommendations? There are two different styles of fan arent there?

 

[71DodgeDemon340]

Anyone know of an sfi approved fan?